Chloro-phosphne-m-carborane and a method of making them

ABSTRACT

CHLOROPHOSPHINE-M-CARBORANES ARE PREPARED BY REACTING DI(ALKALI-METAL)-M-CARBORANES WITH CHLOROPHOSPHINES. THESE COMPOUNDS ARE USEFUL AS FLAME RETARDANTS IN PLASTICS AND COATED PAPER.

United States Patent ()ffi e- 3,637,836 CHLORO-PHOSPHNE-m-CARBORANE ANDA METHOD OF MAKING THEM Roy P. Alexander, Killingworth, and HansjuergenA.

Schroeder, Hamden, Conn., assiguors to Olin Mathieson ChemicalCorporation N Drawing. Original application Feb. 25, 1966, Ser. No.529,944, new Patent No. 3,444,272, dated May 13, 1969. Divided and thisapplication July 31, 1968, Ser.

Int. Cl. C07f 9/52 US. Cl. 260-543 P 10 Claims ABSTRACT OF THEDISCLOSURE Chlorophosphine-m-carboranes are prepared by reactingdi(alkali-metal)-m-carboranes with chlorophosphines. These compounds areuseful as flame retardants in plastics and coated paper.

wherein x is an integer of from 1 to about 10, n is an integer of from 0to 10 inclusive, R is selected from the group consisting of alkyl offrom 1 to carbon atoms and halogen selected from the group consisting ofchlorine, bromine, iodine and fluorine, R is selected from the groupconsisting of chlorine, phenyl, and alkyl-substituted phenyl of not morethan carbon atoms, and with the proviso that when R is alkyl, then 11 is1.

The novel compounds of this invention are prepared by reacting adi(alkali metal)-m-carborane with a phosphine compound of the formula:

wherein R is chlorine, phenyl or alkyl-substituted phenyl of not morethan 10 carbon atoms, at a temperature of from about l0 to about +60 C.and preferably from about 0 to about 35 C. The reaction can beconveniently conducted by adding a slurry of a dilithio-m-carborane inan inert organic solvent to a solution of the phosphine compound in aninert organic solvent. Mixtures of the di(alkali metal)-m-carboranes aswell as mixtures of phosphines can be employed if desired.

Useful inert organic solvents include hydrocarbons such as benzene,toluene, xylene, cyclohexane; loWer-dialkyl ethers, such as diethylether, ethyl propyl ether, di-isopropyl ether, di-n-butyl ether, etc.Generally, from about 0.5 to about 10 moles or more of the saidphosphorus compound will 'be reacted with each mole of the di(alkalimetal)-m-carborane employed although it is preferred to utilize fromabout 1 to about 5 moles of phosphorus trichloride per mole of thestarting di(alkali metal)mcarborane.

Recovery of the products prepared by the reaction of di(alkalimetal)-m-carboranes with the phosphine compound can be accomplished by avariety of methods 3,637,836 Patented Jan. 25, 1972 known in the art.For example, at the conclusion of the reaction, the solvent can beremoved from the reaction mixture by evaporation in vacuo or by anyother convenient method, yielding a residual oil. Monomeric materials ofthe formula:

C1 E CB10H(l0-n)RnC: P

L |x (A) wherein x is 1 and n, R and R have the same meaning aspreviously described, can then be obtained by first extracting theresidual oil with a suitable solvent such as benzene, cyclohexane,heptane, carbon tetrachloride etc. to give a viscous liquid which ondistillation yields as the overhead product monomeric materials ofFormula A (where x is l) and as the bottoms product polymeric materialsof Formula A (where x is greater than 1).

Ortho carborane (i.e., o-carborane) compounds useful ultimately inpreparing the di(alkali metal)-m-car boranes which, in turn, areutilized as starting materials in the method of this invention can beprepared by the reaction of decaborane or an alkylated decaborane havingan alkyl group containing 1 to 5 carbon atoms, with acetylene in thepresence of a wide variety of ethers, amines or nitriles. Thepreparation of these compounds is described in application Ser. No.741,976, filed June 13, 1958 now abandoned of Ager, Heying and Marigold.For example, the compound o-carborane having the formula:

0 BIOHlO can be prepared by reacting for about 12 hours at 125 C. amixture of decaborane and tetrahydrofuran in an autoclave pressured top.s.i. with acetylene.

When o-carboranes of the formula:

HCCH O BmHgRRa borane which has the formula:

BIOHIO can be converted to m-carborane, that is, HCB H CH, by heating ata temperature of 475 C. for 5 to 20 hours. Halogenated m-carboranecompounds can be formed by the methods set forth in Heying and Schroederapplication Ser. No. 414,947, filed Nov. 27, 1964 now US. 3,562,- 324and in Schroeder and Smith application Ser. No. 379,- 859, filed July 2,1964 now abandoned. For example, B- tetrachloro-m-carborane can beprepared by reacting gaseous chlorine with m-carborane in carbontetrachloride and under ultraviolet irradiation.

The di( alkali metal)-m-carborane compounds which are useful as startingmaterials in the process of this invention can be prepared by theprocess described in US. Patent 3,148,219 and have the formula:

wherein n is an integer of from O to 10, M is an alkali metal selectedfrom the group consisting of sodium, lithium, and potassium, R isselected from the group consisting of alkyl of from 1 to 5 carbon atomsand halogen selected from the group consisting of chlorine, bromine,iodine, and fluorine, and with the proviso that when R is alkyl, then Itis 1. For example, C,C-dilithio-m-carborane can be formed by reactingm-carborane with n-butyl lithium in the presence of dialkyl ether.Suitable di(alkali metal)-m-carboranes includeC,C'-dilithio-B-methyl-mcarborane, C,C-dilithio-B-isopropy1-m-carborane,C,C'-dilithio-B-amyl-m-carborane, C,C-dilithio-B-chloro-m-car borane,C,C'-dilithio-B-fluoro-m-carborane, C,C'-dilithio-B-tetrachloro-m-carborane, C,C' dilithio-B-iodo-rn-carborane,C,C-dilithio-B-dibromo-m-carborane,C,C-dilithio-B-heptafluoro-m-carborane, C,C'dilithio-B-decachloro-m-carborane, etc., and the corresponding sodiumand potassium compounds.

Phosphine compounds suitable as starting materials in the method of thisinvention include phosphorus trichloride, phenyldichlorophosphine,dirnethylphenyldichlorophosphine, ethylphenyldichlorophosphine,n-propylphenyldichlorophosphine, isopropylphenyldichlorophosphine, etc.

Treatment of the novel chlorine-terminated m-carborane derivatives ofthis invention at a temperature of from about to about 80 C. with amonohydric alcohol of the formula:

wherein R" is alkyl of from 1 to 10 carbon atoms, results in theformation of alkoxy-substitutcd materials of the formula:

RN! R!!! It"' -1 OB 0II m R,.O-i

wherein x is an integer of from 1 to about 10, n is an integer of from 0to 10 inclusive, R is selected from the group consisting of alkyl offrom 1 to carbon atoms and halogen selected from the group consisting ofchlorine, bromine, iodine and fluorine, each R" is independentlyselected from the group consisting of chlorine, phenyl, andalkyl-substituted phenyl of not more than car bon atoms, and ROH,wherein R is alkyl of from 1 to 10 carbon atoms and each R isindependently selected from the group consisting of chlorine and R"O-,wherein R is alkyl of from 1 to 10 carbon atoms, and with the provisothat when R is alkyl, then It is 1, that when R is phenyl oralkyl-substituted phenyl, both R substituents are the same and that atleast one of R'" and R" is R"O. Generally, from about 5 to about 150moles or more of the monohydric alcohol will be reacted per mole of thestarting chlorine-terminated compound of Formula A. Useful alcoholsinclude methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropylalcohol, n-butyl alcohol, sec.- n-butyl alcohol, amyl alcohol, isooctylalcohol, n-nonyl alcohol, n-decyl alcohol, etc. and mixtures of thesealcohols. Recovery of the alkoxylated compounds is accomplished byevaporating off the alcohol or by any other convenient method.

All of the solid products of this invention (i.e., both monomers andpolymers) can be utilized as flame retardants in plastics, such aspolyethylene, polypropylene, polyvinyl chloride, etc. For example, fromabout 2 to about percent by weight of the polymer formed in Example Ican be blended with polyethylene or with polyethylene and about 5percent by weight of paraffin wax to yield products with highly improvedflame resistance properties. Any suitable process can be used forpreparing the blends such, for example, as Banbury mixers, extrusionmixers, roll mills or solution blending processes well known in the art.The ultimate products can be formed from such blends by solutioncasting, extrusion molding, pressure molding and the like. Formsupported or unsupported films, rods or other shapes can be prepared.

The liquid products of this invention, such as the product of Example HI(i.e., mB H C (C H P-Cl) can be blended with waxes such as petroleum waxor chlorinated parafiin by heating the two materials together at atemperature above the melting point of the wax. Such blended products,which generally contain from about 80 to about 95 percent by weight ofthe wax, can be utilized to prepare coated paper, film etc., having ahigh degree 4 of flame retardance. Coated products can also be preparedby spraying the liquid products of this invention on plastic film orsheet.

In addition, the liquid products of this invention can be used in themanufacture of non-flammable urethane foams. For example, from about 1to about 5 percent or more of the compound:

C1 C1 Ol-l -CB1nHmC-1 Cl can be mixed with tolylene diisocyanate,oxyethylated glycerin of molecular weight 3000; a catalyst such asdibutyl tin dilaurate; a cross-linking agent such as N,N,N, N'-tetrakis(2)hydroxypropy1) ethylene diamine and foamed in the presence of ablowing agent such as trichlorotrifluoroethane, to yield a polyurethaneproduct exhibiting excellent non-burning properties.

The examples which follow illustrate various embodiments of thisinvention and are to be considered not limitative:

EXAMPLE I Dilithio-m-carborane (i.e., LiCB H CLi) (0.42 mole) slurriedin ether (1000 ml.) was added, with stirring and ice-cooling to asolution of PC];, (173 g., 1.26 mole) in ether (2000 ml.) over a 20 min.period. After stirring for 12 hr. at ambient temperature, the solventwas removed in vacuo. The residual oil was extracted with 300 ml.benzene to give, after evaporation of the benzene, a viscous liquidwhich was subjected to vacuum distillation. Yield of the compound of theformula:

('31 (I31 ClP-OB10II1 C1Cl was 59 g. (40 percent); B.P. 119 C. (0.3mm.); 11

AnaZySis.Calcd. for CZH1OB1OCI4P2 (percent): C, 6.94; H, 2.91; B, 31.27;C, 40.98; P, 17.90. Found (percent): C, 6.66; H, 2.90; B, 31.27; C,40.20; P, 17.50. The distillation residue was triturated with coldmethanol to give 30 g. (about 35 percent based on m-carborane startingmaterial) of solid polymeric product, M.P. 35 C.

Analysis.Calcd. for C H B Cl OP (percent): C, 11.23; H, 4.54; B, 45.98;C, 21.09; P, 15.80. Found (percent): C, 11.25; H, 4.58; B, 48.81; C,22.20; P, 15.47. Mol. weight (in toluene at 39 C.): 1117.

Based on the molecular weight and elemental analysis it was determinedthat the formula of the polymer was:

EXAMPLE n EXAMPLE III A dilithio-m-carborane (0.1 mole) solution inether (400 ml.) was added to phenyldichlorophosphine (35.8 g., 0.2 mole)in ether (500 ml.) and allowed to react at a temperature of 10-15 C. Themixture was refluxed for 1 hour, cooled to 20 C. and filtered afterwhich the sol- OCII;

vent was stripped on. The crude product was distilled in vacuo to give25 g. (58.3 percent) of (C H -P Cl)CB H C(C H -P- Cl) having theformula:

ClPCBmH1oCP-Cl B.P. 220 C. (0.35 mm.); 11 1.6522.

Analysis.-Calcd. for C H B Cl P (429.4) (percent): C, 39.16; H, 4.70; B,25.20; Cl, 16.51; P, 14.43. Found (percent): C, 38.70; H, 4.80; B,25.23; Cl, 16.50; P, 14.25.

' EXAMPLE IV grams of (C H5'PCl)CB10H C(C5H5P'Cl), prepared as describedin Example III, was dissolved in 300 ml. of methanol.

After stirring at ambient temperature for 2 hours, the reaction producthad precipitated and was recovered by filtration. Recrystallization frommethanol afforded 22.1 g. (75 percent) of pure product of the formula:

Analysis.-Calcd. for C H B O P (420.5) (percent): C, 45.70; H, 6.23; B,25.73; P, 14.73. Found (per- Cent): C, 45.82; H, 5.95; B, 25.56; P,14.17.

EXAMPLE V An amount of g. of CI PCB H CPCI prepared as described inExample I was dissolved in 50 ml. of methanol. After removal of thesolvent, there remained a colorless liquid m-carborane derivative, freeof chlorine, having the formula:

Analysis.Calcd. for C H B O P (328.4) (percent): C, 21.95; H, 6.75; B,32.95; P, 18.18. Found (percent): C, 20.55; H, 6.51; B, 33.44; P, 18.08.

EXAMPLE VI was washed with ether, then slurried with 250 ml. ether, andadded with ice-cooling to a solution of PCl (41.1 g., 0.3 mole) in 500ml. ether. After stirring for 12 hours at ambient temperature, theresulting mixture was filtered, and then the filtrate evaporated todryness. Trituration of the residue with methanol aiforded 25 g. ofpolymer of the formula:

6 Analysis.Calcd. for C15HG3BGOBIGCI3O3PG (percent): C, 10.52; H, 3.71;B, 37.91; Cl, 6.21; Br, 28.00; P, 10.85. Found (percent): C, 9.67; H,3.68, B, 36.34; Cl, 6.21; Br, 28.00; P, 11.08. Mol. weight (in tolueneat 39 C.): 1784.

What is claimed is: 1. An m-canborane compound of the formula:

I F o1-P l:oB H w n R,.oP-o1 wherein x is an integer of from 2 to about10, n is an integer of from 0 to 10 inclusive, R is a halogen selectedfrom the group consisting of chlorine, bromine, iodine and fluorine, Ris selected from the group consisting of chlorine, phenyl, andalkyl-substituted phenyl of not more than 10 carbon atoms.

2. The compound of claim 1 wherein x is 5, n is 0 and R is Cl.

3. A method for the preparation of an m-carborane compound of theformula:

R R Cll CBinH i0-u RnC1 wherein x is an integer of from 2 to about 10, nis an integer of from 0 to 10 inclusive, R is a halogen selected fromthe group consisting of chlorine, bromine, iodine and fluorine, and R isselected from the group consisting of chlorine, phenyl, andalkyl-substituted phenyl of not more than 10 carbon atoms whichcomprises reacting a phosphine of the formula:

wherein R has the same meaning as previously described, with anm-carborane compound of the formula:

wherein M is an alkali metal selected from the group consisting ofsodium, lithium and potassium and n and R have the same meaning aspreviously described.

4. The method of claim 3 wherein the reaction is conducted at atemperature range of from about 10 to about l+60 C.

5. The method of claim 3 wherein the acid reaction is conducted in thepresence of an inert organic solvent.

6. The method of claim 5 wherein the said solvent is diethyl ether.

7. The method of claim 3 wherein the said phosphine isphenyldichlorophosphine.

8. The method of claim 3 wherein the said phosphine is phosphorustrichloride.

9. The method of claim 3 wherein the said m-carborane compound is:

LiCB H CLi 10. The method of claim 3 wherein from about 1 to about 10moles of the said phosphine are reacted with each mole of the saidm-carborane compound.

References Cited Alexander et al. J. Inorganic Chemistry vol. 2 No. 6(December 1963) pp. 1107-1110.

JAMES A. PATTEN, Primary Examiner E. J. GLEIMAN, Assistant Examiner U.S.Cl. X.R. 204158 HA

